Effects of Transcranial Direct Current Stimulation With Gait Training on Lower Limb Performance in Individual With Incomplete Spinal Cord Injury

The result from the previous studies of Water in 1994 regarding the ambulation status of patients with spinal cord injury (SCI) for a period of 1 year after injury. It was found that 76% of incomplete paraplegia and 46 % of incomplete tetraplegia can recovery their walking ability to become community ambulators. However, the recovery rate gradually decreased and started to hit the plateau level around 9 months post injury or in chronic phase. Therefore, it is a challenge in rehabilitation to restore their functions such as walking which is a primary goal of functional independence.

Activity-based rehabilitation therapy (ABRT) (such as locomotion training) is an intensive intervention that has the potential to promote neurological recovery and enhance walking ability in individual with incomplete SCI. Although, ABRT showed positive results in motor function recovery in incomplete SCI survivors, it may not be able to promote full recovery, especially in chronic patients. Recent studies showed that the combination of training with top-down approach may be an option that could promote motor recovery after SCI.

transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that is currently being used as an add-on treatment in neurorehabilitation. tDCS over the primary motor cortex has been shown to modulate neural activity at both cortical and spinal levels. It also produce an after-effect in modulating neuronal synaptic plasticity and increasing the expression of brain-derived neurotrophic factor (BDNF). Early tDCS studies have shown that increasing stimulation intensity or duration within certain limits enhances tDCS efficacy: while anodal stimulation increases cortical excitability, cathodal stimulation decreases it. The application of tDCS is to place the electrode in a specific montage on the decided target brain area and deliver the low-intensity current pass through that brain area for neural modulation during or after providing a rehabilitation program. Previous studies of the application of tDCS showed that applying of tDCS on primary motor cortex with intensity of 2 milliampere (mA) for 10-20 minutes combined with rehabilitation can enhance lower limb performance such as knee strength, ankle movement, and sit to stand performance in people with stroke as well as walking speed in people with Parkinson's disease. According to result from those previous studies can revealed that the combination of rehabilitation with modulation of corticospinal excitability can enhance lower limb performance in individual with neurological condition. In individuals with incomplete SCI, the excitability of the preserved corticospinal pathways is reduced which can affect the control of their motor skills and motor recovery. Several studies reported positive effect of anodal tDCS combined with training in individuals with incomplete SCI, however most of studies focused on upper limb function. Only few studies on the outcome of lower limb function and walking ability, which are required to return to their daily living and thus increase in quality of life (QOL). Moreover, most of studies in the lower limb were conducted in a small sample size and reported inconclusive results.

Therefore, the purpose of this study is to determine whether the effects of combining anodal tDCS with gait training for 5 consecutive session in people with incomplete SCI can improve lower limb performance consist of gait performance(spatiotemporal), dynamic balance(time up and go test), sit to stand performance (5 times of sit to stand test) and QOL after a prolonged period of follow-up at 1-month and 2-month compare to control group of sham tDCS with gait training.